Re: [PATCH v3 05/43] drm/bridge: analogix_dp: Don't power bridge in analogix_dp_bind

Marek Szyprowski
2018-03-01T08:20:04Z

Hi Heiko,

Thanks for adding me to this thread.

On 2018-02-28 16:20, Heiko Stübner wrote:
> Am Dienstag, 30. Januar 2018, 21:28:35 CET schrieb Thierry Escande:
>> From: zain wang <wzz@rock-chips.com>
>>
>> The bridge does not need to be powered in analogix_dp_bind(), so
>> remove the calls to pm_runtime_get()/phy_power_on()/analogix_dp_init_dp()
>> as well as their power-off counterparts.
>>
>> Cc: Stéphane Marchesin <marcheu@chromium.org>
>> Signed-off-by: zain wang <wzz@rock-chips.com>
>> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
>> [the patch originally just removed the power_on portion, seanpaul removed
>> the power off code as well as improved the commit message]
>> Signed-off-by: Sean Paul <seanpaul@chromium.org>
>> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
>> ---
>> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 10 ----------
>> 1 file changed, 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c index
>> cb5e18d6ba04..1477ea9ba85d 100644
>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>> @@ -1382,11 +1382,6 @@ analogix_dp_bind(struct device *dev, struct
>> drm_device *drm_dev,
>>
>> pm_runtime_enable(dev);
>>
>> - pm_runtime_get_sync(dev);
>> - phy_power_on(dp->phy);
>> -
>> - analogix_dp_init_dp(dp);
>> -
>> ret = devm_request_threaded_irq(&pdev->dev, dp->irq,
>> analogix_dp_hardirq,
>> analogix_dp_irq_thread,
>> @@ -1414,15 +1409,10 @@ analogix_dp_bind(struct device *dev, struct
>> drm_device *drm_dev, goto err_disable_pm_runtime;
>> }
>>
>> - phy_power_off(dp->phy);
>> - pm_runtime_put(dev);
>> -
>> return dp;
>>
>> err_disable_pm_runtime:
>>
>> - phy_power_off(dp->phy);
>> - pm_runtime_put(dev);
>> pm_runtime_disable(dev);
>>
>> return ERR_PTR(ret);
> In general, this patch seems to also create the opposite than
> "drm/bridge: analogix_dp: Keep PHY powered between driver bind/unbind" [0]
>
> posted on monday?
>
> [0] https://patchwork.kernel.org/patch/10242493/

Well, my patch was a quick workaround to avoid board freeze.

This patch looks like a proper fix. Besides removing runtime pm and phy
power calls from dp_bind, it also removes dp register access done in
analogix_dp_init_dp, as there is really no need to touch registers in bind
operation.

The patchset however suffers from other issues on Exynos hardware. I
will post
them in that thread.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland